Apparatus for controlling the flow of gases

ABSTRACT

Apparatus for controlling the flow of a gaseous medium which is supplied into a chamber having an inverted frustro-conical bottom wall disposed below the level of a liquid. Vertically spaced rows of ports in the frustro-conical wall permit the gas to escape for bubbling upwardly through the liquid. The sloping wall makes it possible to provide small differences in the depth of the rows of discharge ports below the level of the liquid whereby the pressure required for gas flow through all the ports is not substantially greater than that for initiating gas flow through the most upstream row of ports.

United States Patent 1191, Zink et al. v

APPARATUS FOR CONTROLLING THE FLOW OF GASES Inventors: John Smith Zink; Robert E.

Schwartz; Robert D. Reed, all of Tulsa, Okla.

Assignee: John Zink Company, Tulsa, Okla.

Filed: Feb. 28, 1973 Appl. No.: 336,829

Related US. Application Data Continuation-impart of Ser. No. 846,404, July 3|, 1969, abandoned.

US. Cl. 137/251, 137/253 Int. Cl. Fl6k 9/00 Field of Search 137/251, 252, 253 254;

References Cited UNITED STATES PATENTS .6/1946 Goldberg 261/124 1451 Apr.9, 1974 2,721,065 10 1955 Ingram 261/124 3.721.429 3/1973 Young 261/123 Prinwry Examiner-Harold W. Weakley Attorney, Agent, or Firm-Clelle W. Upchurch 5 7 ABSTRACT Apparatus for controlling the flow of a gaseous medium which is supplied into a chamber having an inverted frustro-conical bottom wall disposed below the level of a liquid. Vertically spaced rows of ports in the frustro-conical wall permit the gas to escape for bubbling upwardly through the liquid. The sloping wall makes it possible to provide small differences in the depth of the rows of discharge ports below the level of the liquid whereby the pressure required for gas flow through all the ports is not substantially greater than that for initiating gas-flow through the most upstream row of ports.

7 Claims, 3 Drawing Figures APPARATUS FOR CONTROLLING THE FLOW OF GASES This application is a continuation-in-part of our application Ser. No. 846,404 filed July 31, 1969 and now abandoned.

The present invention relates to apparatus for controlling the flow of a gaseous medium and more specifically pertains to a housing containing a quantity of liquid with a discharge head disposed below the level of the liquid through which the gaseous medium escapes to bubble upwardly through the liquid.

It is known to release a gas below the level of a liquid and at different depths below the surface of the liquid so that the gas may bubble upwardly through the liquid and various structural arrangements have been provided in an effort to prevent surging and pressure variations upstream and downstream of such devices.

The principle of water seals for regulation of flow of gases is old. However, as gases pass through the water seals, there can be a singularly undesirable end-result of the passage.

Gases are almost infinitely compressible so long as the state of compression does not convert the gas to a liquid. Liquids 'areto all effects and purposes incompressible and the mass (weight) ratio of liquid to gas exceeds 800 to 1 (water 62.43lbs/cu ft versus air at 0.0763lbs/cu ft). I

In a liquid seal, as gas pressure rises to a condition greater than the static-head of the liquid contained in the dipleg of the seal, there is passage of gas through the seal but not as a continuous stream but as separate bubbles.

As the bubbles disengage from the immersed dip-leg and because of the very great mass difference in view of gas compressibility, there is immediate rebound of liquid into the dip-leg. As a result of the rebound there is instant stoppage of gas flow and instant rise in the pressure on the gas. Such pressure fluctuations are typically as great as alilbs. Such a seal serves its function as a seal, per se, but very undesirably at the upstream side of the seal as well as at the downstream side.

An apparatus having a dip-leg for regulating the pressure of gas flowing from a blast furnace is disclosed in U,S. P at. No. 2,72l,065. The disclosed apparatus has a tubular conduit which extends as a dip-leg into a vessel containingwater. That end of the dip-leg submerged under the water is cylindrical and of the same diameter cumferentially spaced ports are vertically spaced in the conduits wall adjacent toits submerged end. Such an apparatus can-be used to regulate the passage of gases under'relatively high pressures but it has the disadvantage that it cannot be used to discharge a desired volume of gas evenly at low head pressures.

It is thereforean object of this invention to provide an-apparatus for controlling the flow of gases even at relatively low head pressures. A further object of the invention is to provide an apparatus adapted to cause flow of gas upwardly through a liquid to its surface for passage of the gas'in the absence of pressure surges at either the downstream or the upstream side of the liquid because there is neither a state of two-phase flow nor synchronized rebound of liquid counter current to gas flow. Another object of the present invention to provide improvements wherein the ports through which the gas is released are formed in an inverted frustro-conical wall so that small changes in pressures at .as the remainder of the conduit. Parallel rows of cirwhich the gas is delivered into such chamber will cause the gas to be progressively discharged through openings at different levels within the liquid.

Other objects and features of the invention will be appreciated and become apparent as the present disclosure proceeds and upon consideration of the following detailed description taken in conjunction with the accompanying drawing.

In the drawing:

FIG. 1 is a sectional view of apparatus embodying the invention;

FIG. 2 is a sectional view on a larger scale of the discharge head;

FIG. 3 is an inverted plan view of the discharge head and taken on the line 3-3 of FIG. 1.

The invention is directed to apparatus for controlling the flow of gases and includes tubular means for guiding a gaseous medium to a position below the level of a supply of liquid and into an inverted frustro-conically shaped discharge head of greater cross-section at its top than the cross-section of the tubular member. An increase in the flow of the gas causes liquid to be displaced from the head and the gas escapes from discharge ports and bubbles'upwardly through the liquid. The apparatus prevents reverse flow of the gas because such movement of the gas forces the liquid upstream in the device to provide a column of liquid which must be overcome before there can be a reverse flow of the gas.

Referring to the drawing there is shown at 10 a housing which may be of any suitable contruction and designed to contain a quantity of liquid which is maintained at a level 1 l. The liquid may be supplied into the housing through a pipe fitting 12 and a tube 14 controlled by a valve 16 serves to release the liquid from the housing. The housing 10 is provided with a conduit fitting 17 disposed above the level of the liquid and for the escape of the gaseous medium.

A tubular member 18 depends as a dip-leg into the housing 10. It is supported by the top wall 19. The tubular member 18 is sealed with respect to the top wall 19 and serves to guide the gaseous medium into the housing. The tubular member 18 is desirably arranged along the axis of the housing 10. The tubular member 18 depends below the level of the liquidas shown in FIG. 1.

A discharge head 20 carried by the lower end of the tubular member 18 provides a chamber into which the gaseous medium is supplied. The discharge head may take any desired form except that the bottom wall 21 is of inverted frusto-conical shape which slopes at an acute angle with respect to the level of the liquid 11. A plurality of discharge ports 22 are arranged as a row within the sloping wall 21. These discharge ports 22 are circumferentially spaced and arranged symmetrically about the circumference of the discharge head 20. A second rowof discharge ports 23 are provided in the inverted frustro-conical wall and these are arranged symmetrically about the discharge head and circumferentially spaced as shown in FIG. 3. Another row of discharge ports 24 are provided in the inverted frustroconical wall 21 and these are symmetrically arranged about the circumference. As illustrated in the drawing, discharge head 20 has an inverted frustro-conical shape with the base of the inverted frustro-conically shaped portion being of larger diameter than conduit 18. An open ended tubular member 27 is attached to the apex of the frusto-conically shaped portion of head 20 and has a diameter substantially equal to the diameter of conduit 18.

The discharge head 20 is in open communication with the tubular member 18 so that the gaseous medium is supplied into the chamber 26. Short tubular element 27 extends below the inverted frustro-conical wall and provides an escape for the gaseous medium in the event that the discharge ports should become obstructed and thus provides emergency relief for the gas eous medium below the level of the liquid.

Referring to FIG. 2, the vertical distance from the upper edge of ports 22 to the lower edge of ports 24 is shown as H. The total vertical dimension as inches water-column pressure between the top of ports 22 and the lower edge of ports 24, which is H, defines the pressure increment required between very small flow only through ports 22 and design or maximum flow through ports 22, 23 and 24. In other words, the latter dimension in inches represents the difference in pressure in inches water-column required for gas flow to increase from the volume which flows only through ports 22 to the volume which flows through all of the ports 22, 23 and 24. The vertical distance H is less than the distance I-I,,.

It is preferred that the pressure increment from initiation of gas flow to 100 percent design flow from a dipleg operating at relatively low pressure be maintained as small as possible. The low angle of sloping wall 21 with respect to the flat top of head 20, the vertical spacing between the rows of ports 22, 23 and 24 and the dimensions of the ports establish the pressure difference required to initiate flow and to produce 100 percent design flow. In accordance with the invention the wall 21 slopes at an angle of from about 5 to about 80 and preferably from about 20 to about 60 with respect to the flat top of discharge head 20. If wall 21 were in a plane parallel to the plane of the top discharge head 20, there would be partial entrapment of gas in the liquid below wall 21 and there would be great surging of pressure in flow of gas. However, the discharge of gas to liquid from head 20 having sloping wall 21 is not vertically downward and the slope of wall 21 permits upward movement of gas to avoid partial entrapment and to maintain liquid immediately at the exit from the port to receive the gas as it is discharged without surging of pressure as the gas passes. Best results are obtained if the wall 21 converges at an angle of about 30 with respect to the flat top of discharge head 20 so apparatus in which the slopeis at about 30 is preferred.

. As illustrated in FIG. 3, the diameters of the ports 22, 23 and 24 are equal and the number of ports in each circumferential row is equal to provide substantially identical gas discharge area in each row as gas flow volume and pressure increases for gas flow volume/pressure per row of ports which is substantially identical so that, with three rows of ports, the gas flow per row is substantially one-third the'total volume. This is but one port arrangement which is possible in the structure of FIG. 3. The area per circumferential row may be altered as preferred through either other port diameter in each row and/or number of ports in each row.

In operation and when the pressure at which the gaseous medium supplied into the tubular member 18 increases, and is greater than the liquid column above the uppermost areas of the ports 22, the discharge of gas is initiated and it proceeds upwardly through the liquid as a series of bubbles. The ports 22 are located in the largest diameter portion of the discharge head 20 and the release of the gaseous medium through the ports 22 is in areas which are separated from each other to the greatest extent.

As there is an increase in the flow of the gaseous medium as a result of an increase in pressure, a condition will be developed which displaces liquid from the chamber 26 down to the level of the uppermost part of the discharge ports 23 so that the gaseous medium will then also escape through these ports along with gas flowing from the ports 22. As pointed out above, it will be observed from a consideration of FIG. 2 that there is a very small vertical dimension between the uppermost part of the discharge ports 22 from the uppermost parts of the discharge ports 23. A further increase in the flow of the gaseous medium will displace more liquid from the chamber 26 so that gas will then escape from the ports 24. There is a similar small vertical dimension between the uppermost portion of the discharge ports 23 and the uppermost part of the discharge ports 24. If the discharge ports should become obstructed the lower end of the tube 27 is open for the emergency relief of gases into the liquid.

The inverted frustro-conical bottom wall 21 provides space for accommodating dischrge ports which may be circumferentially spaced from each other by relatively large dimensions. The spacing may be greater than the cross-section of the ports. The inverted frustro-conical bottom wall with the ports therein provides a device which will provide for the discharge of a large volume of gases at relatively small changes in the pressure head. Thus, it is possible to cause the bubbling flow of gas upwardly through the liquid to escape through the exit opening 17 with a minimum of pressure surges at the upstream side of the device and at the downstream side of the apparatus because there is never a state of two-phase flow nor synchronized rebound of the liquid counter-current to the flow of the gas.

In the event that there is a decrease in pressure of the gas supplied into the tubular member 18 and an increase in pressure within the housing 10, such a condition causes the liquid to move upwardly into the tubular member 18 and provide a liquid column which must be overcome before there can be any reversed flow of gas through theapparatus.

While the invention has been described with reference to structural features in one type of assembly, it will be appreciated that changes may be made in the details as well as the overall organization. Such modifications and others may be made without departing from the spirit and scope of the invention as set forth in the appended claims.

What is claimed is:

1. Apparatus for controlling the flow of a gas comprising a housing adapted to contain a quantity of liquid, said housing having an opening above the level of the liquid serving as an outlet, a tubular member depending into said housing for guiding a gas under pressure downstream into the housing, a discharge head carried by said tubular member, said discharge head having a top portion of greater cross-section than said tubular member and a downwardly converging bottom wall disposed to be below the level of the liquid contained in the housing, said converging bottom wall being inclined in acute angular relationship with respect to the said top, a plurality of vertically spaced rows of circumferentially spaced ports in said bottom wall, said discharge head having an opening at its apex for escape of gas when gas flow therein exceeds the capacity of said ports, said tubular member serving to accommodate a column of liquid which resists upstream movement of the gas therein from within the housing.

2. The apparatus of claim 1 having plural rows of ports with the cross-section of the ports, the vertical spacing thereof and the said angle being such that the vertical displacement from the top of the uppermost row of ports to the bottom of the farthest downstream row of ports is small.

3. The apparatus of claim 2 wherein the vertical distance between the top of the ports in the most upstream row thereof and the bottom of the ports in the most downstream row is less than the total vertical dimension of the converging bottom wall pierced by the ports.

4. The apparatus of claim 1 wherein said discharge head has a cylindrical sidewall adjacent a flat top enclosing a cylindrical chamber and said bottom wall converges downwardly from the sidewall.

5. The apparatus of claim 1 wherein the total crosssectional area of the said ports in said discharge head is proportional to the cross-sectional area of the said tubular member depending into said housing according spect to the top wall. 

1. Apparatus for controlling the flow of a gas comprising a housing adapted to contain a quantity of liquid, said housing having an opening above the level of the liquid serving as an outlet, a tubular member depending into said housing for guiding a gas under pressure downstream into the housing, a discharge head carried by said tubular member, said discharge head having a top portion of greater cross-section than said tubular member and a downwardly converging bottom wall disposed to be below the level of the liquid contained in the housing, said converging bottom wall being inclined in acute angular relationship with respect to the said top, a plurality of vertically spaced rows of circumferentially spaced ports in said bottom wall, said discharge head having an opening at its apex for escape of gas when gas flow therein exceeds the capacity of said ports, said tubular member serving to accommodate a column of liquid which resists upstream movement of the gas therein from within the housing.
 2. The apparatus of claim 1 having plural rows of ports with the cross-section of the ports, the vertical spacing thereof and the said angle being such that the vertical displacement from the top of the uppermost row of ports to the bottom of the farthest downstream row of ports is small.
 3. The apparatus of claim 2 wherein the vertical distance between the top of the ports in the most upstream row thereof and the bottom of the ports in the most downstream row is less than the total vertical dimension of the converging bottom wall pierced by the ports.
 4. The apparatus of claim 1 wherein said discharge head has A cylindrical sidewall adjacent a flat top enclosing a cylindrical chamber and said bottom wall converges downwardly from the sidewall.
 5. The apparatus of claim 1 wherein the total cross-sectional area of the said ports in said discharge head is proportional to the cross-sectional area of the said tubular member depending into said housing according to preferred discharge flow pressure drop in passage of gas from the said discharge head to the said liquid contained within said housing.
 6. The apparatus of claim 1 whereby after passage of said gas through said ports to said liquid there is ready escape of said gas from the vicinity of said ports.
 7. The apparatus of claim 1 wherein the bottom wall is inclined at an angle of about 5* to about 80* with respect to the top wall. 